A year ago Lisa Bernstein rescued Ringo, an 8-week-old German shepherd pup, from the Tri-County Humane Society. The high-spirited dog became her teenage son's best friend, though the pooch didn't much like others.

In hopes of getting him to behave, Bernstein, of suburban Boca Raton, hired Jill Deringer, a dog trainer whom she met at Petco in Boca Raton and whom she now blames for killing her family's beloved pet

The woman came into my house with a dog that was in perfect health. She sat on my dog for one hour and killed him," Bernstein said, weeping.

Deringer, of Lake Worth, who claims to have successfully trained more than 1,700 dogs, some even more aggressive than Ringo, used what some trainers call a questionable technique, muzzling the dog and holding him down to show him who's the boss. She's been on national talk shows displaying her ability to bark like 200 breeds of dogs.

"I do an alpha role. Many trainers do this. I hold it down to prevent myself from being bitten," Deringer said. "I am a huge animal lover. This was just a tragedy."

Palm Beach County Animal Care and Control is investigating the dog's death, which occurred Sunday night after Ringo was rushed to an emergency animal hospital suffering from what appeared to be heat stroke. A necropsy is planned, said Dianne Sauve, the agency's director.

"There are red flags going up with tactics that may have been taken," she said.

Bernstein, who also filed a report with the Palm Beach County Sheriff's Office, blames herself, in part, for the dog's demise.

"This was a year-and-a-half-old vibrant, healthy puppy that she tortured for one hour, and I allowed it because she kept telling me over and over again that he was OK," Bernstein said.

Bernstein's experience serves as a cautionary tale for other dog owners looking for trainers.

"Anybody can be a dog trainer; there is no licensing, certification or requirement," said Chris Altier, a trainer with the National K-9 School for Dog Trainers in Columbus, Ohio. "There are situations where you might have to restrain a dog, but I have never heard of anybody having to do that," he said, referring to Deringer's training method.

A qualified trainer, said Altier, should have recognized the signs of stress before the dog's condition became critical.

Deringer said she was simply holding the dog â€” kneeling over him, but not applying her full weight â€” to prevent him from kicking her. Despite those efforts, she said, "He struck me over 100 times. I have the scratches to prove it."

When Ringo finally calmed, Deringer took off the muzzle but he just sat there panting. That had never happened before, she said.

She and Bernstein quickly put the dog into a tub of water to cool it down and then called Bernstein's vet. Because it was late on a Sunday night, he urged her to take the dog to the emergency clinic. By the time they got there, Ringo was blind and showed signs of internal bleeding. A couple of hours later, the clinic called to say he had taken a turn for the worse and had little chance of survival. That's when Bernstein agreed to let them put Ringo to sleep.

Deringer said the whole situation is "sad and emotional."

A spokesman for Petco, where Deringer worked, said company officials were aware of the situation and were looking into it.

"This is unfortunate all around. What this person did is something she is responsible for, and we are investigating it fully and will take appropriate actions," said Don Cowan from the company's corporate office in San Diego, Calif.

Cowan said their trainers go through a certification program that includes classroom training and some on-the-job training with other trainers.

It's unclear what training techniques Deringer used while at Petco, but Stephen Zawistowski, a certified applied animal behaviorist with the American Society for the Prevention of Cruelty to Animals in New York, said the "alpha dog" method is based on concepts that are 20 to 30 years old.

"Theoretically, beating kids with a strap used to keep them behaved, but we don't do that any more," Zawistowski said. "Our concept is that humane training does not inflict unnecessary distress or discomfort."

On Tuesday, Bernstein got a call from Jeannette Christos of the Tri-County Humane Society that another German shepherd, one the same age as Ringo, was available for adoption. Her family had moved to Costa Rica and couldn't keep her.

It was a "beshert," Yiddish for "meant to be," said Bernstein. "This dog needed us and we needed her. She is going to help us heal."

There was a video about this on CNN and in the video it said the woman was also poking the dog all over, like she was trying to aggravate him. Craziness. What kind of owner stands by and lets this happen?

"Remember - every time your dog gets somewhere on a tight leash *a fairy dies and it's all your fault.* Think of the fairies." http://www.positivepetzine.com"

i have seen this done before and didn't like it .
i think this proves that no one method of training works on every dog.
i do think hired trainers can be helpful, dog owners should be the ones doing the hands on training under the direction of a trainer, that way you are in complete control.
if you have a problem with your dog YOU need to fix it if someone else fixes the problem the dog hasn't learned YOU are the boss.
trainers should only be hired when all else fails, not as a easy solution.
the best training is done with lots of hands on time from his/her master.